The present invention is directed to a temporary supporting device for plate-like workpieces, such as sheets of paper or cardboard, within a delivery station of machine that is processing these workpieces.
A machine for processing sheet-like workpieces usually includes an infeed station in which a pile of sheets is arranged. Each sheet is successively taken from the top of the pile in order to be carried onto a feeding table. Once on the feeding table, every sheet is positioned against from lays and side-marks prior to being seized on its front edge by a series of grippers mounted on a crosswise bar, whose ends are attached to a pair of lateral continuous chains which are arranged for transferring the bar and sheet in succession through the processing stations. The processing stations can consist of a die-cutting press, which is then followed by a waste stripping station. These processing stations are followed by a delivery station in which every sheet is released by the grippers end is aligned when dropping on top of a stack or pile being formed on an outlet pallet. This pallet is carded by a plate-like elevator which is lowered as the pile grows in order to keep the top of the pile at a constant level with regard to the machine or device.
When the outlet pile has a predetermined number of sheets, a temporary supporting device is inserted in the path of the dropping sheets in order to support the next sheets as the pile on the pallet is removed. In the meantime, the elevator is brought back to ground level and the full pallet is removed prior to being replaced by an empty pallet. The plate is then raised again until the empty pallet takes over supporting the weight of the new pile which is being built up, at which time the temporary supporting device is retracted to deposit the temporary pile on the pallet.
A known semi-automatic supporting device includes a horizontal track or cradle, for example a frame which carries a pair of lateral grooves, one on both sides of the pile. This device includes a so-called non-stop grid or grate which is made of a plurality of parallel and horizontal forks which are held together with crossbars connected to two lateral lengthwise beams. These lengthwise beams have, moreover, a plurality of outer rollers engaged in the grooves of the track or cradle. This arrangement allows for a manual movement of the grid in the tracks of the cradle in order to place it in direct alignment with the passage of the sheets or to move it to a retracted position to withdraw it from the path of the sheets being delivered. The cradle can be moved in translation by a vertical jack slowly downward in the course of the building up of the temporary pile on the engaged grid and quickly upward with the grid in a disengaged position for coming back to a starting position for the cradle.
It has appeared, however, that the grid in its disengaged or retracted position, although functioning satisfactorily, will protrude from the delivery station and could become an almost permanent danger for inattentive operators who could hurt themselves on it. This danger is also present if the grid is not completely engaged when being used, as in the case for the delivery of small-sized sheets and, therefore, partially protrudes from the delivery station.